scholarly journals Actin Filaments Play a Critical Role in Vacuolar Trafficking at the Golgi Complex in Plant Cells

2005 ◽  
Vol 17 (3) ◽  
pp. 888-902 ◽  
Author(s):  
Hyeran Kim ◽  
Misoon Park ◽  
Soo Jin Kim ◽  
Inhwan Hwang
Keyword(s):  
Golgi Complex ◽  
Actin Filaments ◽  
Critical Role ◽  
Plant Cells ◽  
Vacuolar Trafficking

Confocal microscopy of the cytoskeleton in living plant cells following microinjection of fluorescent probes

1993 ◽  
Vol 51 ◽  
pp. 130-131
Author(s):  
Ann Cleary
Keyword(s):  
Cell Division ◽  
Fluorescent Probes ◽  
Actin Filaments ◽  
Intracellular Transport ◽  
Cell Structure ◽  
Plant Cells ◽  
Cell Plate ◽  
Cell Cortex ◽  
Living Plant ◽  
Rhodamine Phalloidin

Microinjection of fluorescent probes into living plant cells reveals new aspects of cell structure and function. Microtubules and actin filaments are dynamic components of the cytoskeleton and are involved in cell growth, division and intracellular transport. To date, cytoskeletal probes used in microinjection studies have included rhodamine-phalloidin for labelling actin filaments and fluorescently labelled animal tubulin for incorporation into microtubules. From a recent study of Tradescantia stamen hair cells it appears that actin may have a role in defining the plane of cell division. Unlike microtubules, actin is present in the cell cortex and delimits the division site throughout mitosis. Herein, I shall describe actin, its arrangement and putative role in cell plate placement, in another material, living cells of Tradescantia leaf epidermis.The epidermis is peeled from the abaxial surface of young leaves usually without disruption to cytoplasmic streaming or cell division. The peel is stuck to the base of a well slide using 0.1% polyethylenimine and bathed in a solution of 1% mannitol +/− 1 mM probenecid.

scholarly journals Rha1, an Arabidopsis Rab5 Homolog, Plays a Critical Role in the Vacuolar Trafficking of Soluble Cargo Proteins

2003 ◽  
Vol 15 (5) ◽  
pp. 1057-1070 ◽  
Author(s):  
Eun Ju Sohn ◽  
Eol Sun Kim ◽  
Min Zhao ◽  
Soo Jin Kim ◽  
Hyeran Kim ◽  
...  
Keyword(s):  
Critical Role ◽  
Cargo Proteins ◽  
Vacuolar Trafficking

Abstract P392: The Effect Of Cell Sex On Magnetic Nanoparticle Uptake Of Human Induced Pluripotent Stem Cell-derived Cardiomyocytes

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Morteza Mahmoudi ◽  
Vahid Serpooshan ◽  
Phillip C Yang ◽  
Mahyar Heydarpour
Keyword(s):  
Heart Failure ◽  
Actin Filaments ◽  
Electromechanical Coupling ◽  
Critical Role ◽  
Induced Pluripotent Stem Cell ◽  
Patient Specific ◽  
P Value ◽  
Male And Female ◽  
Cell Therapies ◽  
Human Cardiomyocytes

Introduction: It is well understood that the occurrence, progress, and treatment of heart failure, which is a leading cause of death worldwide, is sex-specific. Over the past decade, the majority of efforts in myocardial regeneration have been centered on cell-based cardiac repair. A promising cell source for these efforts is patient-specific human cardiomyocytes (CMs) differentiated from human inducible pluripotent stem cells (hiPSCs). However, successful use of hiPSC-CMs faces a major limitation, the poor engraftment and electromechanical coupling of transplanted cells with the host myocardial tissue. Magnetic nanoparticles (NPs) demonstrate great potential to address this challenge for treating heart failure via cell therapies. In particular, superparamagnetic iron oxide NPs (SPIONs) have been used to label hiPSC-CMs and, with the aid of external magnetic field, improve their engraftment and electromechanical coupling in the heart tissue. However, the critical role of cell sex in the uptake and labeling efficacy of NPs has not been evaluated. Hypothesis: Significant differences in the molecular and structural (e.g., actin structures and distribution) characteristics of male and female hiPSC-CMs affect their labeling efficacy with SPIONs. Methods and Results: To test our hypothesis, we first performed RNA-Seq analysis on three male and three female (healthy) hiPSC-CM lines. The normalized outcomes were analyzed by edgeR package. We next calculated gene-expression differential between male and female CMs. The results revealed 58 genes with significant differences between the male and female cells (p-value < 0.01). The highest observed sex-specific variation in genes was related to tophit gene (MEG3: logFC = 7.32, P-value = 5.63e -06 ), which is the maternally expressed imprinted gene with a great role in cardiac angiogenesis. Among the identified genes, a number of those were related to the cellular cytoskeletal structures including actin. We probed possible structural differences between actin filaments organization and distribution of male and female hiPSC-CMs using the stochastic optical reconstruction microscopy (STORM) technique. The results demonstrated substantial differences in organization, distribution, and morphology of actin filaments between male and female CMs. Incubation of SPIONs with male and female hiPSC-CMs revealed higher uptake of NPs (~ 3 folds) in female cells as compared to the male cells. The significant differences in the uptake of SPIONs by male vs. female cells could be attributed to the distinct organization, distribution, and morphology of actin in male vs. female cells. Conclusions: Our results indicate that male and female hiPSCs-CMs respond differently to the labeling SPIONs.

scholarly journals Myosin Motors and Not Actin Comets Are Mediators of the Actin-based Golgi-to-Endoplasmic Reticulum Protein Transport

2003 ◽  
Vol 14 (2) ◽  
pp. 445-459 ◽  
Author(s):  
Juan M. Durán ◽  
Ferran Valderrama ◽  
Susana Castel ◽  
Juana Magdalena ◽  
Mónica Tomás ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Golgi Complex ◽  
Light Chain ◽  
Shiga Toxin ◽  
Actin Filaments ◽  
Protein Transport ◽  
Myosin Ii ◽  
Nonmuscle Myosin ◽  
Nonmuscle Myosin Ii ◽  
Myosin Motors

We have previously reported that actin filaments are involved in protein transport from the Golgi complex to the endoplasmic reticulum. Herein, we examined whether myosin motors or actin comets mediate this transport. To address this issue we have used, on one hand, a combination of specific inhibitors such as 2,3-butanedione monoxime (BDM) and 1-[5-isoquinoline sulfonyl]-2-methyl piperazine (ML7), which inhibit myosin and the phosphorylation of myosin II by the myosin light chain kinase, respectively; and a mutant of the nonmuscle myosin II regulatory light chain, which cannot be phosphorylated (MRLC2AA). On the other hand, actin comet tails were induced by the overexpression of phosphatidylinositol phosphate 5-kinase. Cells treated with BDM/ML7 or those that express the MRLC2AA mutant revealed a significant reduction in the brefeldin A (BFA)-induced fusion of Golgi enzymes with the endoplasmic reticulum (ER). This delay was not caused by an alteration in the formation of the BFA-induced tubules from the Golgi complex. In addition, the Shiga toxin fragment B transport from the Golgi complex to the ER was also altered. This impairment in the retrograde protein transport was not due to depletion of intracellular calcium stores or to the activation of Rho kinase. Neither the reassembly of the Golgi complex after BFA removal nor VSV-G transport from ER to the Golgi was altered in cells treated with BDM/ML7 or expressing MRLC2AA. Finally, transport carriers containing Shiga toxin did not move into the cytosol at the tips of comet tails of polymerizing actin. Collectively, the results indicate that 1) myosin motors move to transport carriers from the Golgi complex to the ER along actin filaments; 2) nonmuscle myosin II mediates in this process; and 3) actin comets are not involved in retrograde transport.

scholarly journals Signals from the spindle midzone are required for the stimulation of cytokinesis in cultured epithelial cells.

1996 ◽  
Vol 7 (2) ◽  
pp. 225-232 ◽  
Author(s):  
L G Cao ◽  
Y L Wang
Keyword(s):  
Epithelial Cells ◽  
Mitotic Spindle ◽  
Actin Filaments ◽  
Cultured Cells ◽  
Critical Role ◽  
Equatorial Region ◽  
Culture Cells ◽  
Cultured Epithelial Cells ◽  
Early Anaphase ◽  
Spindle Midzone

The interaction between the mitotic spindle and the cellular cortex is thought to play a critical role in stimulating cell cleavage. However, little is understood about the nature of such interactions, particularly in tissue culture cells. We have investigated the role of the spindle midzone in signaling cytokinesis by creating a barrier in cultured epithelial cells with a blunted needle, to block signals that may emanate from this region. When the barrier was created during metaphase or early anaphase, cleavage took place only on the sides of the cortex facing the mitotic spindle. Microtubules on the cleaving side showed organization typical of that in normal dividing cells. On the noncleaving side, most microtubules passed from one side of the equator into the other without any apparent organization, and actin filaments failed to organize in the equatorial region. When the barrier was created after the first minute of anaphase, cells showed successful cytokinesis, with normal organization of microtubules and actin filaments on both sides of the barrier. Our study suggests that transient signals from the midzone of early anaphase spindles are required for equatorial contraction in cultured cells and that such signaling may involve the organization of microtubules near the equator.

A high molecular weight polypeptide cross-reacting with the antibodies to the dynein heavy chain localizes to the subset of Golgi complex in higher plant cells

2009 ◽  
Vol 33 (3) ◽  
pp. 290-300 ◽  
Author(s):  
Nina A. Shanina ◽  
Elena M. Lazareva ◽  
Ekaterina Y. Skorova ◽  
Yuri S. Chentsov ◽  
Elena A. Smirnova
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Heavy Chain ◽  
Golgi Complex ◽  
Plant Cells ◽  
Higher Plant ◽  
Dynein Heavy Chain

scholarly journals Association of myosin with the connecting cilium of rod photoreceptors

1992 ◽  
Vol 103 (1) ◽  
pp. 183-190 ◽  
Author(s):  
D.S. Williams ◽  
M.A. Hallett ◽  
K. Arikawa
Keyword(s):  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Actin Filaments ◽  
Critical Role ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Vertebrate Photoreceptor ◽  
Sds Page ◽  
Membrane Morphogenesis ◽  
Muscle Myosin

The cilium of a vertebrate photoreceptor cell connects the phototransductive outer segment of the cell to the inner segment. Previous studies have shown that, within the connecting cilium, there is a small cluster of actin filaments, which play a critical role in the formation of new disk membranes. Here, we have detected a polypeptide in rat rod outer segments that is recognized by myosin heavy chain antibodies and was found to possess other characteristics of conventional non-muscle myosin heavy chain: it comigrates in SDS-PAGE with non-muscle myosin heavy chain; it associates with the cytoskeleton of rod outer segments in an ATP-sensitive manner; and it binds to purified actin filaments in the absence of ATP. Myosin ATPase activity was also detected in isolated rod outer segments. Electron immunomicroscopy revealed that myosin is present in the small actin-containing domain within the connecting cilium at the site of disk membrane morphogenesis. These results pose the possibility that an actin-myosin contractile mechanism functions in the formation of new photoreceptor disk membranes.

scholarly journals Pointed-end capping by tropomodulin3 negatively regulates endothelial cell motility

2003 ◽  
Vol 161 (2) ◽  
pp. 371-380 ◽  
Author(s):  
Robert S. Fischer ◽  
Kimberly L. Fritz-Six ◽  
Velia M. Fowler
Keyword(s):  
Cell Migration ◽  
Cell Motility ◽  
Actin Filament ◽  
Actin Filaments ◽  
Critical Role ◽  
Leading Edge ◽  
Average Cell ◽  
Transient Overexpression ◽  
End Capping ◽  
Pointed End

Actin filament pointed-end dynamics are thought to play a critical role in cell motility, yet regulation of this process remains poorly understood. We describe here a previously uncharacterized tropomodulin (Tmod) isoform, Tmod3, which is widely expressed in human tissues and is present in human microvascular endothelial cells (HMEC-1). Tmod3 is present in sufficient quantity to cap pointed ends of actin filaments, localizes to actin filament structures in HMEC-1 cells, and appears enriched in leading edge ruffles and lamellipodia. Transient overexpression of GFP–Tmod3 leads to a depolarized cell morphology and decreased cell motility. A fivefold increase in Tmod3 results in an equivalent decrease in free pointed ends in the cells. Unexpectedly, a decrease in the relative amounts of F-actin, free barbed ends, and actin-related protein 2/3 (Arp2/3) complex in lamellipodia are also observed. Conversely, decreased expression of Tmod3 by RNA interference leads to faster average cell migration, along with increases in free pointed and barbed ends in lamellipodial actin filaments. These data collectively demonstrate that capping of actin filament pointed ends by Tmod3 inhibits cell migration and reveal a novel control mechanism for regulation of actin filaments in lamellipodia.

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